Reflective insulation has little effect on heat transfer by conduction through the air between hot and cold surfaces. Air with an R-per-inch of 5.6 is an excellent insulator when radiation and convection are controlled. The installation of reflective insulation in an enclosed space reduces thermal radiation to near zero. When the reflective insulation is installed to subdivide an air-filled region then convection is also reduced.
AA2 Vapor Shield
VR Plus Shield